[imp] empty trash / empty spam / empty folder

[Liam Hoekenga]

>> Should the status messages / UI elements be updated to reflect that the 
>> messages have only been deleted a not expunged?  "Emptied all messages from 
>> /foldername/" really says to me that the has been emptied, and for that to 
>> happen, they need to be deleted /and/ expunged.
>
> I was actually wrong. Looking at the code, the mailbox *is* expunged if not 
> using a trash folder, or if emptying the trash folder.

Our experience with both 4.2RC2 and HEAD that the mail is not expunged, 
only marked deleted.

Liam